Figure 1. Model of triptolide release from minnelide. Minnelide consists of a phosphonooxymethyl prodrug group that increases the compound's solubility in water.

Phosphatases, which are present in blood and many bodily tissues, cleave the phosphate group from minnelide to yield an unstable O-hydroxymethyl intermediate. This intermediate then degrades into formaldehyde and the anticancer compound triptolide.